Cleavage of Ni-(μ2-S)-Ni Bridges in Dinuclear Nickel(II) Dithiolate Pincer Complexes and Related Reactions

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• 作者：Deguang Huang ; Liang Deng ; Jibin Sun ; R. H. Holm
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：July 6, 2009
• 年：2009
• 卷：48
• 期：13
• 页码：6159-6166
• 全文大小：942K
• 年卷期：v.48,no.13(July 6, 2009)
• ISSN：1520-510X

文摘

Pyridine-2,6-dimethanethiolate and pyridine-2,6-dithiocarboxylate form sparingly soluble Ni^II pincer complexes formulated as [Ni(pdmt)]₂ and [Ni(pdtc)]₂, respectively, with two Ni-(μ₂-S)-Ni bridges. In acetonitrile reaction systems, the latter undergoes the facile bridge cleavage reactions [Ni(pdtc)]₂ + 2L^0,− → 2[Ni(pdtc)L]^0,− with an extensive set of nucleophiles to afford planar mononuclear products with L⁻ = halide, CN, Me₃SiO⁻, RS⁻ and L⁰ = Et₃P and a N-heterocyclic carbene. [Ni(pdmt)]₂ is considerably less reactive toward bridge disruption. Cleavage products support several reactions of interest leading to other mononuclear species and to di- and trinuclear complexes. [Ni(pdtc)(OSiMe₃)]¹⁻ deprotonates acetonitrile and acetone to form [Ni(pdtc)(CH₂R)]¹⁻ (R = CN, COMe). Reaction of [Ni(pdtc)SEt]¹⁻ with Fe^II yields the thiolate-bridged dimer {[Ni(pdtc)]₂(SEt)}¹⁻. Refluxing an acetonitrile solution of [Ni(pdtc)SH]¹⁻ in air results in formation of trinuclear [Ni(pdtc)]₃S]²⁻ containing the rare unsupported Ni₃(μ₃-S) bridge core. Reaction of [Ni(pdtc)CN]¹⁻ with [Fe(Me₆tren)(OTf)]¹⁺ forms the complex [Ni(pdtc)CNFe(Me₆tren)]¹⁺, the only example of a single Ni−C≡N−Fe bridge within a molecule. Structures of the various types of reaction products are presented. This work demonstrates the potential utility of bridge cleavage of polynuclear Ni^II thiolates, an extensive family of compounds, to produce mononuclear products.